Sparking plug for internal combustion engines



June 5, 1934.

A. KEGRESSE SPARKING PLUG FOR INTERNAL COMBUSTION ENGINES 2 Sheets-Sheet1 Filed Dec. 4, 1951 F191.

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June 5, 1934. KE E E 1,962,079

SPARKING PLUG FOR INTERNAL COMBUSTION ENGINES Filed Dec. 4, 1951 2Sheets-Sheet 2 Fig.5

Patented June 5, 1934 UNITED STATES SPARKING PLUG FOB INTERNALCOMBUSTION ENGINES Adolphe Kegresse, Courbevoie, France ApplicationDecember 4, 1931, Serial No. 579,086

In France December 6, 1930 Claims.

This invention relates to improvements in and relating to the spark plugdescribed in the application for an American patent number U. S. A.476,391 of August 19th 1930 and has for its 5 object, on the one hand,materially to increase the continuity of the wall surface in theexplosion chamber, such a condition being necessary for reducing thepossibility of ignition troubles and, on theother hand, to reduce thespace required for the insertion of said spark plug.

In the appended drawings Figure 1 is an elevational view of a sparkingplug for a water-cooled'motor, said spark plug being designed accordingto the present addition.

Figure 2 is a sectional view of said spark plug through the line IIII ofFigure 1.

Figure 3 is an elevational view of the same spark plug for anair-cooledmotor.

Figure 4 is a sectional view through the line 20v IV--IV of Figure 3.

In all the figures, 1 .is the insulating material of the spark plug.Said insulating material is located in a hollow body 2 of suitable form(Figures 1 and 2).

Said hollow body 2 is threaded in its upper part into the outer wall 3ofthe cylinder head (Figures 1 and 2) and on the other side it rests inits lower part 4 (which is shown here as a truncated point) against theinner wall 5 of the explosion chamber 6.

Said hollow body 2 is locked ontothe outer wall 3 of the cylinder headthrough a lock nut '7 working onto a joint 8 (Figure 1).

Between the lower part 4 of the hollow body 2 and the upper part of thesame is provided a middle part 9 which is entirely immersed into thewater of the chamber 10 of the cylinder head (Figure 1).

In air-cooled motors the middle part 9, which is provided with ribs, iscooled bythe surrounding air playing about said ribs.

The lower part 4 of the hollow body is provided with a small openingthrough which the electrode 11 of the spark plugpasses, leaving be-.tween itself and the opening the necessary interval for the jumping ofthe sparks.

As will be easily seen, the space required by the new form of, sparkplug is comparatively spark plug being extremely smaller than theopening required for ordinary spark plugs.

The cooling of the spark plug is ensured, since the middle part of thehollow body containing conical section of smallest diameter surroundtheinsulating material is provided with thin walls and directly immersedinto the cooling fluid.

What I claim is:

1. In an internal combustion engine, a combustion chamber the wall of.which is provided with an opening into which extend the electrodes of aspark plug, said spark plug comprising a thin-walled tubular casingthrough which extends an insulated central electrode, the. end of saidcasing entering into the opening of the wall of the combustion chamberbeing tapered inwardly to form a frusto-conical section on the end ofthe casing, the pontion of the frustoing the end of the centralelectrode and spaced therefrom a distance equal to the desired sparkgap, theopening in the wall of the combustion chamber being conicallyformed to receive the frusto-conical end of the spark plug and of a sizesufficiently small to expose only the end face of the frusto-conical endof the casing of the spark plug and the central electrode.

2. In an internal combustion engine, a combustion chamber the wall ofwhich is provided with an opening into which extend the electrodes of aspark plug, said spark plug comprising a thin-walled tubular casingthrough which extends an insulated central electrode, the end of saidcasing entering into the opening of the wall of the combustion chamberbeing tapered inwardly to form a frusto-conical section on the end ofthe casing, the portion of the frusto-conical section of smallestdiameter surrounding the end of the central electrode and spacedtherefrom a distance equal to the desired spark gap, the opening in thewall ofthe combustion chamber being conically formed to receive thefrustoconical end of the spark plug and of a size sufiiciently small toexpose only the end face of the frusto-conical end of the casing of thespark plug and the central electrode, and means for directly contactinga cooling medium with the thin-walled casing of the spark plugexteriorly of the combustion chamber. 7

3. In an internal combustion engine, a combustion chamber the wall ofwhich is provided with an opening into which extend the electrodes of aspark plug, said spark plug comprising a thin-walled tubular. casingthrough which extends an insulated central electrode, the end of saidcasing entering into the opening of the wall of the combustion chamberbeing tapered inwardly to form a frusto-conical section on the end ofthe casing, the portion of the frusto-conical section of smallestdiameter sur-- rounding the end of the central electrode and spacedtherefrom a distance equal to the desired spark gap, the opening in thewall of the combustion chamber being conically formed to receive thefrusto-conical end of the spark plugand of a size .sufllciently small toexpose only the end face of the frusto-conical end of the casing of thespark plug and the central electrode, a cooling medium jacketsurrounding the combustion chamber and the spark plug casing in such amanner that a cooling medium in said jacket will contact directly withthe exterior of the thin-walled casing of said spark plug.

4. In an internal combustion engine, a combustion chamber the wall ofwhich is provided with an opening into which extend the elec-- trodes ofa spark plug, said spark plug comprising a thin-walled tubular casingthrough which the thin-walled hollow body of the spark plug sufficientlysmall to expose only the end face of the frusto-conical end of thecasing of the spark plug and the central electrode, and air cooling finson the exterior of the spark plug. casing to dissipate heat into thesurrounding atmosphere.

5. In an internal combustion engine, a combustion chamber, a wallsurrounding the combustion chamber to provide a cooling jacket for thecombustion chamber, said cooling jacket wall and the wall of thecombustion chamber having aligned openings, a spark plug comprising ahollow body with thin walls screwed into the opening in the wall of thejacket and extending through the jacket into the opening in the wall ofthe combustion chamber, so that the exterior thereof will bedirectlyexposed to a cooling medium in the jacket, the opening in thewall of the combustion chamber being in the form of a conical valve seatand the end of 9 being conically tapered inwardly so as to provide arestricted'opening therein and adapted to be received on the conicalseat, and an insulated electrode extending axially through the 1thin-walled hollow body and terminating at the restricted portionthereof, said restricted portion being of a diameter to provide a sparkgap between it and the electrode.

ADOLPHE KEGRESSE. 10

